Bridge



. (No Model.)

I 0. e DIBBLE;

Y BRIDGE. 310193.427. Patented'feb. 12,15 4.

Nrrnn Sr-A'rns CHAUNCEY G. DIBBLE, OF FARMINGTON, IOWA, ASSIGNOR OF ONE-HALF TO FREDERICK E. BANGS, OF NEW HAVEN, CONNECTICUT.

BRIDGE.

SPECIFICATION formingpart of Letters Patent No. 293,427, dated February 12, 1884.

Application filed November :26, 1883.

To all whom it. 11mg concern:

Be it known that 1,0HAUN E G. DIBBLE, of Farmington, in the county of Van Buren, and State of Iowa, have invented a new Improvement in Bridges; and I do hereby declare the following, when taken in connection with the accompanying drawings and the letters of reference marked thereon, to be afull, clear, and exact description of the same, and which said drawings constitute part of this specification, and represent, in

Figure 1, aside view; Fig. 2, an under side View, looking up; Fig. 3, a transverse section at the point where the suspensionrods connect with the chords, enlarged; Fig. 4, an enlarged perspective View, showing the connec tion between the suspension-rods and chords.

This invention relates to an improvement in the construction of that class of bridges in which an arched beam is arranged to support the platform, the horizontal thrust of the arch resisted byahorizontal tie extending from one end of the arch to the other on substantially the chord line, and commonly called bowstring-bridge, the object of the invention being to connect the chord to the arch at intervals in such a manner that the chord itself aids in giving rigidity to the platform over and above that which it naturally gives when employed simply as a chord, and'also to prevent possible transverse vibration of the bridge; and the invention consists in the construction, as hereinafter described, and more particularly recited in tlieclaim.

A represents the arched beam, springing from a suitable block or abutment, B, at each end.

C C are the cross-ties upon which the plat form rests.

D is the chord running from end to end of the beam A, and is preferably made of a pair of cables. On this chord the ties 0 rest, and between the ties C and the beam A struts a are arranged to fix the distance between the ties and the beam. From the beam, and near the point where the struts bear, suspendingrods b extend down to a point, say, about flush with the top of the ties. These suspendingrods are bent into V shape, the bend of the V being at the 'bottom,and the two ends secured in the beam, as shown. Through the angle of the V the chord D takes a bearing, as at (Z.

This is best done, as seen in Fig. 3, by plac- (No model.)

ing of the chord gives to it a brace-like effect,

and great stability to the bridge.

To resist lateral vibration, I arrange beneath the platform curved tie-rods or cables E. These rods start from near the foot of each truss or beam, and curve inward to near the center of the bridge, thence returning to the foot at the other end. At each tie connection is made with the tie-rods E. These tie-rods thus arranged form arches to resist transverse strain or vibration, giving to the platform, transversely, substantially such a support as the arched beam gives to the bridge vertically, and so that the bridge, when complete, is a solid structure, substantially as firm trans-I versely as vertically. It cannot under any influence sway or attain any lateral vibration.

\Vhile I prefer to bend the rods 1) b at their point of connection with the chords, these rods may be made separately and arranged in the same diagonal position to the struts, the two between each pair of struts brought substantially together midway between the ties, and connected with the chords at that point.

[I claim The combination of the arched beams A, the transverse ties C, carrying the platform, vertical struts a between said ties and beam, chords D, extending from the foot of the arch at-one end to the foot at the opposite end, and the diagonal suspension-rods b, extending from the arch near the struts to the chord intermediate between the ties, and there connected with the chord at a point above the plane of the bottom of the ties, whereby an upward bend is produced in the chords between the ties, substantially as described.

cHAUNoEY e. DIBBLE.

WVitnesses:

H. L. DIBBLE, J. W. RICE.

lCO 

